With respect to toner binders for electrophotography for use in a thermo-fixing system that is generally used as a fixing system for an image in a copying machine, a printer and the like, characteristics, such as preventing a toner from being fused to adhere to a hot roll even at a high fixing temperature (hot offset resistance), making a toner fixable even at a low fixing temperature (low-temperature fixing property) and storage stability, have been demanded.
Toner compositions that comprise a polyester-based toner binder and are superior in both of low-temperature fixing property and hot offset resistance have been known (see Patent Documents 1 and 2). In recent years, however, demands for storage stability and exhibiting both of low-temperature fixing property and hot offset resistance (a fixing temperature range) have become higher and higher, and the demands have not been satisfied sufficiently.